What is the potential of quantum computing for business? Although it is difficult to predict all future uses for a quantum computer (they are still theoretical), Richard Murch tells us why we should put this technology on our watch list.

From the author of

From the author of

Introduction

With quantum computing, we are witnessing an exciting and very promising
merging of three of the deepest and most successful scientific and technological
developments of modern era: quantum physics, computer science, and
nanotechnology. Although experimental developments are in their infancy, there
have already been a variety of concepts, models, methods, and results obtained
at the theoretical level that clearly demonstrated the lasting value and much
future potential. Quantum theory is not new; from its birth in 1900, quantum
mechanics has had an unreal, too-strange-to-be-true quality to it.

Computing design is currently still following the traditional approach of
struggling to squeeze more devices onto a computer chip. Suppose, however, that
we wanted to make extremely small computers—say the size of just a few
atoms. We would no longer be governed by classical laws, but by the laws of
quantum mechanics and nanotechnology.

A vivid and dramatic example of quantum computing can be made with a
comparison against conventional computing architectures of today. Consider the
need for a software program that analyzes every possible combination of 100
flipped coins, which means that there are 2 to the power 100 possible
configurations. Using a traditional PC with 32-bit architecture and a 2
gigahertz clock speed would require in excess of 1 trillion continuous computing
years to complete (the age of the known universe is just over 20 billion years).
A quantum computer with 100 quantum bits could accomplish the same task in less
than a second. Although this is a simple example, it does illustrate the
potential of this computing paradigm when it will be used for computing
intensive problems in science, astronomy, physics, and other related fields.

All we actually need are "bits" that communicate. An atom or
nucleus will do just as well as binary notation because they are natural
"spin-systems." They have measurable physical parameters that we can
use to store information by associating them with different states.

What gives this potential is that there are no further limitations on size
imposed by quantum mechanics, unlike classical computers. To explain what makes
quantum computers so different from their classical counterparts, we can begin
by having a closer look at a basic chunk of information—one bit. From a
physical point of view, a bit is a physical system that can be prepared in one
of the two different states representing two logical values: no or yes, false or
true, or simply 0. (More on this in the next section). The bit is the basis of
quantum computing and what the excitement is about for those who research and
develop it.

The first generation of quantum computers will have components that behave
according to quantum mechanics, but the algorithms that they run will probably
not involve quantum mechanics. No matter how fast conventional computers become,
there will always be some calculations that are too large for them to complete
in reasonable time. Hoping to circumvent these limitations, physicists have
begun to seriously entertain the possibility that a radically different type of
computing could solve certain kinds of problems that a conventional computer
could not solve in the lifetime of the universe (as the example of the 100
flipped coins illustrates).